1. Field of the Invention
This invention relates to refrigeration of perishables, and in particular to a refrigerated case cover.
2. Background of the Invention
Refrigerated cases are in extensive use for cold storage of food. One type of refrigerated food storage case which is very common in supermarkets, food stores, and convenience stores is the open front merchandising case. This type of case comprises a cooling unit installed within an insulated case, and most of the front of the case is open in order to permit customers to easily remove the items desired. Shelves are typically provided on which to store the vendible items.
One such typical retail refrigerated case 2 is illustrated in FIGS. 1 and 2. FIG. 1 is a front quarter isometric view of an open front refrigerated case 2. FIG. 2 is a side cross-sectional view of refrigerated case 2 taken at section II--II of FIG. 1.
Referring now to these two figures, refrigerated case 2 comprises case front 4 and case sides 6. Case front opening 8 is disposed in case front 4; one case side opening 10 is disposed in each case side 6. Case front opening 8 communicates with case side openings 10.
Shelves 14 are disposed within refrigerated case 2 to support vendible refrigerated items. Refrigerated air emerges through grille 12 disposed along lower case front upper edge 20. Grille is comprised of grille apertures 16 separated by grille spokes 18. When provided the requisite electrical power, a modern refrigerated case 2 will maintain food cold enough for adequate preservation.
If electrical power to refrigerated case 2 is interrupted, however, refrigerated case 2 is no longer able to maintain the proper storage temperature, and sooner or later perishable items contained therein will spoil. Power interruptions may occur for a variety of reasons: there may be a problem with the electrical utility which provides power, wind storms may have downed lines, or in the case of a hurricane, power may be interrupted for days. Where a hurricane causes a prolonged power outage, all the perishable items in a refrigerated case may spoil, at considerable cost. For example, following a recent hurricane-induced power outage, the contents of only one refrigerated supermarket dairy case had to be discarded, at a cost of $20,000!
In addition, short of an actual power failure, it would be desirable to insulate case front opening 8 and case side openings 10 during periods that the store is closed, in order to reduce refrigeration costs. If these openings could be temporarily blocked during hours of store closure, less electrical power would be required to maintain the correct temperature inside refrigerated case 2. Given the number of food stores in existence, and the proliferation of refrigerated cases therein, the cumulative energy savings could be considerable.
Existing Designs
A number of solutions have been proposed to the problem of refrigeration failure caused by power outages. One scheme involves a stand-alone generator on-site which would kick in if power failed. A drawback to this solution is cost--a generator sufficiently large to power all the food refrigerators in a modern supermarket is very costly.
Another procedure used when a supermarket experiences what is forecast to be a lengthy power failure, involves moving all the food in open-front refrigerated cases into the walk-in freezer. Due to its closed construction, the walk-in freezer generally stays cold longer than any open-front refrigerated case. In addition, dry ice may be brought into the walk-in freezer to maintain its temperature. As long as the supply of dry ice is kept up, the temperature in the walk-in freezer can be maintained. One major problem associated with this procedure is the large amount of work required to first de-stock, and then after restoration of power re-stock, the open-front refrigerated cases. Another problem is the uncertainty of knowing when power will be restored: it would be a waste of manpower to de-stock the open-front cases, only to have power come back on just as the last case was de-stocked!
Still another procedure currently in use is to prop corrugated cardboard up over the front and side openings of open-face refrigerated cases in case of power failure. Unfortunately, the cardboard tends to get soggy due to water condensation on its inside face. Soggy cardboard is weak cardboard. Customers during a hurricane-induced power outage wishing to purchase food items stored in an open-face refrigerated case blocked by sodden cardboard generally just rip off the water-weakened cardboard, take what they want, and leave. The result is an open-face refrigerated case with no cover to help maintain temperature, and consequent food spoilage. Still another problem associated with using cardboard to maintain temperature inside an open-face refrigerated case is its lack of insulation value: corrugated cardboard provides very little insulation value.
A number of patents have been granted for open front refrigerated case covers. U.S. Pat. Nos. 4,392,360 and 4,141,611 were granted Gidge at al. and De Leon, respectively. The covers disclosed in these patents attached to a case front top by means of hook and loop material and "Y" hooks, respectively. The Gidge et al. '360 patent taught no insulation. Although the De Leon '611 taught insulation, it was fiber glass. If for some reason glass fibers were to escape from the De Leon '611 cover (e.g. due to cover breach or tearage due to folding, etc.), the glass fibers would sprinkle down over food contained in the case, which could constitute a health hazard to anyone subsequently eating the food. In addition, neither of these patents taught a means of securing the bottom of the cover to the case, so customers could easily move these covers aside to remove the refrigerated case contents, allowing the cold air to escape. Finally, both these designs required some modification to the refrigerated case (either holes drilled to accommodate the "J" hooks or hook and loop material mounted to the case front top), so installation required some effort.
Layne, Gidge et al. and Edwards were granted U.S. Pat. Nos. 4,429,548, 4,296,792 and 5,431,490 respectively for ribboned case cover designs. These designs provided a series of ribbons hanging vertically across the case openings. The ribbons were held in place by means of snaps, double-sided tape, or hinged doors (in the case of Layne). These designs suffered from the same disadvantage as the previous two patents: no means of preventing customer access and the attendant loss of cold air was taught. In addition, these designs required some modification to the refrigerated case (permanent installation of doors, snaps, or double-sided tape placement), so installation was permanent and required some effort.
Yet another class of refrigerated case covers were taught in U.S. Pat. Nos. 5,171,076, 4,310,044, 4,288,992, 4,186,790, and 3,241,899, granted to Eming, Schencker, Eliason, Schenker et al. and Donker respectively. These devices were relatively complex, and all taught some means of rolling up the cover in order to retract it. These designs suffered from the disadvantages of complexity, and attendant high cost. In addition, they required permanent installation, and modification to the refrigerated case in which they were installed, thus increasing the cost of installation. Many of these designs taught a ribboned cover, or one which was not secured to the case along its bottom, which allowed customers to open them during power failures, which would allow the cold air to escape.